The original vacuum pipe was black with white plastic nipples that support various vacuum systems. Not knowing what body its hard to guess. Presuming you have a 123 body. The lines coming from the nipples are green: A/C, brown: shut-off function, yellow: door locks, black: early cruise control. Also black lines go to trans control on 80 and newer models.
If the line involved is the trans control the nipple has a very important oriface size and you should replace the vacuum pipe. The others can be variously fixed.
Bosch Master, ASE Master, L1
33 years MB technician